As the integrations of renewable energy generation (REG) within smart distribution networks (SDN) increasing, power flow algorithms (PFAs) of SDN needs special treatment to handle multiple REG. In this paper, the development of PFA is described. According to the control and characteristics of output power (OP), REG can be specified as constant-power-factor (CPF) model and constant-voltage (CV) model. In this paper, these two models are integrated into the proposed PFA. This PFA is capable of switching the REG mode of operation from one model to other with the existence of multiple REGs. The influence of REG on voltage profile and power loss on 15-bus and 69-bus distribution networks (DN) is analyzed with several case studies. And the results are quite promising and are in agreements with the literature.